Semiconductor devices are used in many electronic and other applications. Semiconductor devices comprise integrated circuits that are formed on semiconductor wafers by depositing many types of thin films of material over the semiconductor wafers, and patterning the thin films of material to form the integrated circuits.
Metallization layers are usually the top-most layers of semiconductor devices. The manufacturing of semiconductor devices is typically classified into two phases, the front end of line (FEOL) and the back end of line (BEOL). The BEOL is typically considered to be the phase of the manufacturing process where metallization layers are formed, and the FEOL is considered to include the manufacturing processes prior to the formation of metallization layers.
While some integrated circuits have a single top layer of metallization, other integrated circuits comprise multi-level interconnects, wherein two or more metallization layers are formed over a semiconductor wafer or workpiece. Each conductive line layer typically comprises a plurality of conductive lines separated from one another by an insulating material, also referred to as an inter-level dielectric (ILD). The conductive lines in adjacent horizontal metallization layers are connected vertically in predetermined places by vias formed between the conductive lines.
One of the challenges in semiconductor technology requires developing technologies that minimize process cost while maximizing performance and reliability. Reliability critical applications include aeronautics, space/satellites, automotive, medical, industrial applications. This is because failure of the product during use in one of these applications has severe consequences. For example, in case of failure, danger of injury and death (aeronautics, automotive), risk of expensive consequences (industrial: line stop, major damage to material, equipment etc.), and/or impossibility, impracticability or very high cost of repair (medical implants, space). Hence, a given technology is optimized in view of the process limitations. A challenge in forming vias relates to the avoidance of defects, which impact reliability. Thus, what are needed in the art are cost effective ways of forming BEOL metallization without significant increase in costs or yield, performance and reliability loss.